1. Field of the Invention
The invention relates to an apparatus for producing defined torsional vibrations in a mechanical transmission. Specifically, this apparatus is designed to introduce predetermined torsional vibrations into a drive system which vibrations correspond to those produced by a reciprocating combustion engine.
2. Description of the Prior Art
Reciprocating piston internal-combustion engines, under the influence of periodic forces of gases and gravity, inevitably produce torsional vibrations. These torsional vibrations are transferred to or superimposed on downstream, driven components.
Testing is required to develop drive train components that are incorporated into mechanical transmissions, particularly those of motor vehicles powered by reciprocating combustion engines, e.g., transmissions, drive shafts, axle assemblies and the like. This testing requires that the components be subjected for long periods of time to the effects of torsional vibrations produced by the reciprocating combustion engine.
However, using reciprocating combustion engines in this testing results in undesirably high and unrecoverable energy input. Also, the exhaust and noise produced places a heavy stress on the environment.
In the search for drive systems for testing such components that cost less to operate and pose less danger to the environment, first consideration was given to an electrical drive system. With such a test set-up, some of the energy input could be recovered in a generator. However, electric motors produce no usable torsional vibrations. Therefore, a device had to be developed that would act on the drive train in such a way that torsional vibrations would be simulated in the components to be tested. These vibrations had to correspond, as much as possible, to the vibrations normally produced by reciprocating combustion engines.
Conversely, it is equally useful to provide a device for producing torsional vibrations such as a reciprocating combustion engine would produce, and to place this device in a drive train of a reciprocating combustion engine. This device could then be used to compensate for or dampen the torsional vibrations produced by the reciprocating combustion engine.